Although MRI testing is becoming increasingly important in diagnostic medicine, it is contraindicated for some patients. Such contraindication may result from an active implanted medical device (also referred to below as “implant” or “IMD”). Besides MRI testing, however, other technical applications pose a risk to the user of medical devices or implantable medical devices, particularly when such applications generate strong electromagnetic interference (EMI) fields in their surroundings.
In order to still allow MRI testing, various approaches are known which relate either to performing the MRI testing or to the implantable medical device.
Among others, technologies based on conventional processes for identifying magnetic fields are known for detecting magnetic fields. U.S. 2008/0154342 describes a method which uses a giant magnetoresistance (GMR) sensor to detect problematic magnetic fields from MRT devices. In addition, U.S. Pat. No. 7,164,950 describes an approach for detecting interference fields typical for MRT, the object of which is to detect radio frequency (RF) fields by use of additional antennas, although in this respect an additional sensor is always necessary for detecting magnetic fields. Thus, the system described in the prior art has several disadvantages, such as the deactivation of relevant functions, for example antibradycardial stimulation, the presence of filtered and unfiltered passages into the implant, and the required adjustment of the RF detector using a magnetic field sensor.
What is needed is a way to provide a simple and reliable device and method for detecting typical MRT fields.